Which are the basis of the maximum size of aggregates?
ASTM C 125 defines the maximum aggregate size in one of two ways: Maximum size. The smallest sieve through which 100 percent of the aggregate sample particles pass. Superpave defines the maximum aggregate size as “one sieve larger than the nominal maximum size” (Roberts et al., 1996).
Why maximum size aggregate is important in the mix design of concrete?
Using larger coarse aggregate typically lowers the cost of a concrete mix by reducing cement requirements, the most costly ingredient. Less cement (within reasonable limits for durability) will mean less water if the water-cement (w/c) ratio is kept constant.
What are the sizes of aggregate?
Coarse Aggregate
| Coarse aggregate | Size |
|---|---|
| Medium gravel | Ad 8mm – 16mm |
| Coarse gravel | 16mm – 64mm |
| Cobbles | Ad 64mm – 256mm |
| Boulders | >256mm |
How does the water absorption of the coarse aggregate affect the mix design of concrete?
That is why it greatly affects the concrete mix design. Its properties such as strength, maximum size, shape, and water absorption influence water demand, the quantity of cement and fine aggregate in concrete mixture. This possibility of segregation is minimized if coarser aggregate is properly graded.
What are concrete aggregates?
Concrete aggregates are composed of geological materials such as gravel, sand and crushed rock. The size of the particles determines whether it is a coarse aggregate (e.g. gravel) or a fine aggregate (e.g. sand). The resulting concrete can be used in its natural state or crushed, according to its use and application.
How do you determine the maximum size of coarse aggregate to be used in concrete?
Conditions That Decide Maximum Size of Coarse Aggregate to be Used in Concrete. It should not be more than one fourth of the minimum thickness of the member provided that the concrete can be placed without difficulty so as to aurround all reinforcement thoroughly and fill the corner of the form.